Accelerometer and method of making an accelerometer that senses acceleration in an out-of-plane sensing direction

摘要

PROBLEM TO BE SOLVED: To provide an accelerometer that senses out-of-plane acceleration without requiring additional cost and physical space. An accelerometer includes a proof mass attached to a fixed substrate and a first in-plane direction perpendicular to the sensing direction so that the accelerometer can linearly move in the out-of-plane sensing direction according to applied acceleration. A first and a second set of movable capacitance electrode fingers that extend laterally from the proof mass and are laterally spaced apart in a second in-plane direction perpendicular to the sensing direction, and And a corresponding set of fixed capacitive electrode fingers attached to the substrate, wherein the thickness of the first set of fixed fingers is less than the thickness of the first set of movable fingers, The thickness of the second set is thicker than the thickness of the second set of movable fingers. In use, each adjacent pair of interdigitated fingers has an electric field between their opposing faces. When the fingers of each set are mated together, the degree of "overlap" between the facing surfaces of the thinned and thickened fingers determines the electric field, and thus the capacitance, between the mating fingers. [Selection diagram] Fig. 7B